The rapper - who celebrated her 28th birthday on Sunday (11 October) - immediately realised her error and turned off her phone in a bid to stop it being uploaded.
However, by the time she had turned her phone back on and deleted it, 'everybody and their mom saw my big a** salami nipple t*****s', she said in a subsequent clip.
Cardi - whose song 'WAP' recently topped the UK singles chart - said in a voice note posted on Twitter: "Lord, why the f*** you have to make me so f***ing stupid? Why, why, why?
"You know what, I'm not going to beat myself up about it.
"I'm just going to eat my breakfast and then I'm going to go to the party.
"I am not going to think about it... No, I won't. It is what it is. S*** happened.
"F*** it, it's not even the first time. I used to be a stripper so whatever.
"Ay, dios mio."
Cardi B also responded to people on social media who somewhat intrusively decided to ask about the size of her areolas.
She said: "I breastfed a baby for three months t*****s got bigger so nipples got bigger."
Cardi - who has more than 90 million followers across Instagram and Twitter - has been inundated with support from her fans since she accidentally shared the nude, with many fans sharing topless photos under the hashtag #BoobsOutForCardi.
In September, Cardi filed for divorce from rapper Offset - with whom she has a two-year-old daughter.
Explaining why she was separating from him, she said: "I just got tired of arguing. I got tired of not seeing things eye to eye.
"When you feel like it's not the same anymore, before you actually get cheated on, I'd rather just be, you know what I'm saying?
"Like, I'm tired of people.
"I want to say thank you to everybody they've been showing me love.
"I'm great. I'm okay. I'm not down. I'm not devastated. I'm not hurt."